U.S. patent application, Ser. No. 110,046 filed Jan. 7, 1980 and incorporated herein for purposes of reference, discloses the placement of molecular sieve material both in the flow and return paths of the condensable dielectric coolant used in vapor-cooled transformers. The placement of the molecular sieve material in the path of the vaporized coolant provides for the removal of a quantity of water vapor from the coolant in vapor form. The molecular sieve material in the liquid return path removes any water existing when the coolant is in condensed form.
Since water is continuously evolved from the cellulosic insulation material used within the transformer winding, a substantial quantity of molecular sieve material must be employed within the vapor path in order to insure that the molecular sieve material does not become saturated and inoperative over the entire life of the transformer.
It has since been determined that the more efficient mechanism for water adsorption is when the water is in a condensed state upon contact with the molecular sieve-adsorbing surface. The proper placement of molecular sieve material thereby allows a smaller quantity of sieve material to be employed at a substantial saving both in transformer size and in the quantity of molecular sieve material employed.
The purpose of this invention is to describe an arrangement for using small quantities of molecular sieve material efficiently employed for water adsorption and means for removing and replacing the molecular sieve material upon saturation.